@burnout426 said in Uninstall Opera makes Microsoft Excel 2013 not working Properly:
For testing, you could delete Opera-related keys/strings one by one while testing after each delete to see if you can narrow it down. I'd start with the StartMenuInternet ones.
Opera Stable string in "HKEY_LOCAL_MACHINE\SOFTWARE\RegisteredApplications"
Opera Stable string (if it's there) in "HKEY_CURRENT_USER\Software\RegisteredApplications"
Opera Stable key (if it's there) in "HKEY_CURRENT_USER\Software\Clients\StartMenuInternet"
(There could be multiple keys that when deleted trigger a fix (because the deletion breaks an association), but it's worth a try.)
I'd also look at "HKEY_CLASSES_ROOT" and check the extension keys for any extension that might be handled by Excel/Office (like .xls/.doc etc.) and check their OpenWithProgram IDs or Persistent handler IDs to see if Opera (or its ID (do a search for the id)) is listed there. I'd also look for excel-related keeys in "HKEY_CLASSES_ROOT".
It will take a while to test, but i think it's worth the try. I will keep you in touch of the progress